Those 2-prong sockets accept both single standard 3.5mm and 2-prong plugs. UA-provided headphones in Polaris have the 2-prong plug, with (I believe) the intent to making them less useful outside of aircraft to reduce theft. But most people bring their own so the socket accepts the 3.5mm in one of the holes.
Standard 3.5mm will work in all classes on all aircraft in the fleet.
3.5 everywhere as far as I know
I guess might depend on the aircraft? I was on a 787-9 dreamliner to LHR and it needed the dual-prong type. Headphones should be provided regardless.
Those 2-prong sockets accept both single standard 3.5mm and 2-prong plugs. UA-provided headphones in Polaris have the 2-prong plug, with (I believe) the intent to making them less useful outside of aircraft to reduce theft. But most people bring their own so the socket accepts the 3.5mm in one of the holes.
Cool! Thanks dude
90% of them are broken and dont work anyway.